Salivary gland tumor fine-needle aspiration cytology: a proposal for a risk stratification classification.

OBJECTIVES: Fine-needle aspiration (FNA) is useful in the evaluation of salivary gland tumors, but currently no standard terminology or risk stratification model exists. METHODS: FNA smears were reviewed and categorized based on cytonuclear features, stromal characteristics, and background characteristics. Risk of malignancy was calculated for each category. Classifications as benign, neoplasm of uncertain malignant potential (NUMP), suspicious for malignancy, and positive for malignancy were used to aggregate categories into similar risk groups. RESULTS: Categorization of salivary gland aspirates into morphologic categories resulted in the expected risk stratification. Grouping of categories maintained risk stratification, providing classes with malignancy risk as follows: benign, 2%; NUMP, 18%; suspicious for malignancy, 76%; and positive for malignancy, 100%. CONCLUSIONS: Salivary gland FNA categorization into commonly encountered morphologic categories provides risk stratification, which translates to a simplified classification scheme of benign, NUMP, suspicious, and positive for malignancy similar to the paradigm in other organ systems.